The present invention relates to the driving fit rivet made of aluminum, wherein aluminum plates can be caulked and jointed with high operation efficiency and simplification of recycling and lightening of products can be possible even though the rivet is made of the same material as aluminum plates.
Hitherto, a driving fit rivet for caulking and jointing aluminum plates is generally made of iron steel or stainless steel in order to ensure joint strength and to prevent buckling the driving fit rivet itself when the rivet is drove in. However, the driving fit rivet made of iron steel or stainless steel had problems: whereof a crack is often caused on aluminum plates when the rivet is drove in at the time of jointing aluminum plates without making a prepared hole because the rivet hardness is higher than the aluminum plate""s and the difference is large; also, an electric corrosion and coming a head off by a difference of a coefficient of thermal expansion are often caused because a different series of metal are used.
In resent years, since recycling of raw materials comes to be strongly demanded, and from a viewpoint of that simplification of distinguishing at the time of scraping, driving in to caulk and joint with using the rivet that is made of the same material as the aluminum plate is demanded; however, uniting with using a traditional rivet made of aluminum has a problem whereof mechanical strength is insufficient.
Moreover, for uniting aluminum plates that made of JIS 6000 series alloy, there are experiments whereof aluminum rivets, which are made of JIS 2000 series alloy and JIS 7000 series alloy that are possible to be thermal treated, are used; however, they have no practical use because a electric corrosion problem by potential difference occurs.
In order to solve said electric corrosion problem, using an aluminum rivet that made of the same JIS 6000 series alloy can be considered; however, the hardness of the aluminum rivet that made of the same JIS 6000 series alloy is only Hv from 110 to 120 or so, it is impossible to drive in and unite without making a prepared hole, and even if the prepared hole is made, there is a problem whereof the rivet itself fractures because rivet strength is weaker than work strength.
The object of the present invention is to provide the driving fit rivet made of aluminum whereof, when driving in the rivet to caulk and joint without making a prepared hole on aluminum plates, no crack, no buckling, no seizure, and the like are caused, it is possible to caulk and joint aluminum plates with high operation efficiency and certainly, and it is superior in recycling, additionally it is possible to lighten products of automobile, etc.
In the present invention, the invention relates to claim 1 is the driving fit rivet made of aluminum, which is made of JIS 6000 series aluminum alloy, JIS 6000 series aluminum alloy means Alxe2x80x94Mgxe2x80x94Si series aluminum alloy prescribed in JIS (Japanese Industrial Standard) including JIS 6061, JIS 6N01, JIS 6063, JIS 6101, and JIS 6151; in U.S. standard, ASTM 6000 series aluminum alloy, ASTM 6061 and ASTM 6063; in German standard, DIN 6000 series aluminum alloy, EN AW-6061 and EN AW-6063; and in International standard (ISO), AlMg1SiCu and AlMg0.7Si, and has a head and a shank, wherein surface hardness of said shank is Hv 135 or more.
The invention relates to claim 2 is the driving fit rivet made of aluminum as claimed in claim 1, which is obtained by cold pressing a wire rod of JIS 6000 series aluminum alloy.
The invention that relates to claims 3 and 4 is the driving fit rivet made of aluminum as claimed in claim 1 or 2, wherein a hardening layer depth of a shank is from 0.01 to 0.30 mm.
The invention relates to claims 5 and 6 is the driving fit rivet made of aluminum as claimed in claim 1 or 2, wherein a hardening layer is formed on a shank surface with cold pressing by forming a irregularity whereof a longitudinal direction is the same as the axis direction.
The invention relates to claims 7 and 8 is the driving fit rivet made of aluminum as claimed in claim 1 or 2, which shank has hardness of two-layered structure whereof core hardness of the shank is approximately Hv from 110 to 120.
The invention relates to claims 9 or 10 is the driving fit rivet made of aluminum as claimed in claim 1 and 2, wherein a shape from a periphery of the head to the shank is a curved shape.